This paper presents a new solution for a battery discharge regulator for high-power space applications (power-per-module ≥ 5 kW) using a high-efficiency step-up converter. Basic requirements are efficiency that is higher than 97%, mass that is lower than 2.5 kg, no galvanic isolation necessary, and a high mean time between failures. By taking into account all these parameters, the selected topology has been two interleaved boost converters with passive soft switching. Small-signal analysis of these two interleaved boost converters is also presented.